| Roger Halebæk Transport AS | Transport & logistics | 2013 |
| Rognlien Olsen AS | | 2023 |
| Rolando AS | Real estate | 2017 |
| Roma Mineralvannfabrikk AS | Manufacturing | 2017 |
| Roma-Holding AS | Manufacturing | 2017 |
| Romer Eiendom AS | Real estate | 2006 |
| Romer Entreprenør AS | Real estate | 2026 |
| Romer Utvikling AS | Real estate | 2023 |
| Romerike Allmennspesialistene AS | Health & social care | 2015 |
| Romerike Bilskadesenter AS | Other services | 2021 |
| Romerike Boliginvest Ans | Real estate | 2005 |
| Romerike Boligutvikling AS | Real estate | 1993 |
| Romerike Bunadtilvirker AS | Wholesale & retail | 2016 |
| Romerike Facility Service AS | Administrative & support | 2021 |
| Romerike Hjertesenter AS | Health & social care | 2015 |
| Romerike Oppmåling AS | Professional & scientific | 1997 |
| Romerike Parkering AS | Transport & logistics | 1998 |
| Romerike Profilteknikk AS | Construction | 1994 |
| Romerike Sparebank | Financial services | 1923 |
| Romerike Spesialistklinikk Lege Og Tannlege AS | Health & social care | 2013 |
| Romerikes Blad AS | Information & communication | 1996 |
| Romeriksmegleren AS | Real estate | 1996 |
| Romerikspsykologene AS | Real estate | 2009 |
| Rondheim AS | Financial services | 2009 |
| Ronsan AS | Wholesale & retail | 2013 |
| Rosalie Investment AS | Information & communication | 2022 |
| Roschtorp AS | Health & social care | 2024 |
| Rosenberg Spiseforretning AS | Manufacturing | 2006 |
| Roxane AS | Real estate | 2019 |
| Royal Hair AS | Other services | 2021 |
| RS Eiendom Øst AS | Real estate | 2010 |
| RSB Eiendom AS | Real estate | 2026 |
| Ruan Holding AS | Financial services | 2005 |
| Rud Terrasse Holding AS | | 2026 |
| Rugtvedt Næringspark AS | Real estate | 2024 |
| Rush Invest AS | Real estate | 2024 |
| Russgo AS | Wholesale & retail | 2022 |
| Ruud Holding AS | Real estate | 1997 |
| RWR AS | Professional & scientific | 2006 |
| Rydje & Sønner Holding AS | | 2026 |
| Rydéns AS | Wholesale & retail | 2006 |
| Ryen Antikk AS | Wholesale & retail | 2026 |
| Romerike Glass A/S | Construction | 1973 |
| Révele AS | Other services | 2024 |
| Røch Transport AS | Transport & logistics | 2015 |
| Rørlegger På Hjul AS | Construction | 2020 |
| Rørtema AS | Construction | 2014 |
| Rørtema Prosjekt AS | Construction | 2023 |
| Røst Eiendomsselskap AS | Real estate | 2019 |
| S Hollie AS | Real estate | 1993 |
| S-K Portservice AS | Construction | 2011 |
| S.H. Invest AS | Health & social care | 2018 |
| S2 Invest AS | | 2024 |
| Sabb AS | Real estate | 2011 |
| Sabrura Lillestrøm AS | Hospitality | 2022 |
| Sadol AS | Wholesale & retail | 2023 |
| Safetyrespect Nuf | Administrative & support | 2013 |
| Sagmoen Eiendomsutvikling AS | Real estate | 2018 |
| Sagmoen Holding AS | Real estate | 2018 |
| Sagmoen Prosjekt AS | Real estate | 2011 |
| Sagvik Holding AS | | 2023 |
| Sala Thai AS | Wholesale & retail | 2016 |
| Salg Og Monteringsservice Ans | | 1986 |
| Salvatori Bygg Og Entreprenør AS | Construction | 2019 |
| Samvirkeforetaket Vann- Og Avløp Buerstad | Construction | 2023 |
| Sandakerveien 70 AS | Real estate | 2013 |
| Sandberg Invest AS | Professional & scientific | 2015 |
| Sandum Finans AS | Professional & scientific | 2018 |
| Sandum Invest & Regnskap AS | Professional & scientific | 2009 |
| Sandvik AB | Professional & scientific | 2000 |
| Sannergata 13 A-B Holding AS | | 2024 |
| Sansenes Hage AS | Wholesale & retail | 2001 |
| Sant Og Usant AS | Information & communication | 2005 |
| Sarec Lønn AS | Professional & scientific | 2019 |
| Sariel AS | Wholesale & retail | 2021 |
| Sasa D AS | Real estate | 2010 |
| Saturn Ans | Wholesale & retail | 1999 |
| Sava International AS | Professional & scientific | 2025 |
| Sava Sustainable Solutions AS | Wholesale & retail | 2022 |
| Saxi Produkter AS | Wholesale & retail | 1979 |
| SBS Entreprenør AS | Construction | 2013 |
| SC Holdings AS | | 2024 |
| Scalability AS | | 2022 |
| Scaleup Lillestrøm AS | Real estate | 2019 |
| Scandinavian AS | Wholesale & retail | 2013 |
| Scandinavian Pharma Group AS | Wholesale & retail | 2025 |
| Scandinavian Weldtech AS | Professional & scientific | 2006 |
| Scenebredden AS | Arts & recreation | 2025 |
| Scenekafeen AS | Hospitality | 2013 |
| Schmidt Invest AS | | 2019 |
| Scoops Norge AS | Hospitality | 2024 |
| Scoore AS | Information & communication | 2024 |
| SDN Oppmåling AS | Professional & scientific | 2006 |
| Sea Candy AS | Wholesale & retail | 2025 |
| Seavesselmanager AS | Information & communication | 2026 |
| Sebastian Ramsland Invest AS | | 2022 |
| Secure Art Care AS | Transport & logistics | 2025 |
| Sed Holding AS | | 2025 |
| See Boligeiendom AS | Real estate | 2025 |
| See Holding AS | | 2025 |